The present invention relates generally to an improved drive system for a snowmobile, and more specifically to a snowmobile having a suspension/traction unit designed to have a two stage angle of attack with a low primary angle of attack. The traction unit is suspended relative to the chassis of the snowmobile and includes a secondary angle of attack for accelerating in deep snow and a primary angle of attack for high speed travel and starting out on surfaces where the snow is less deep or is compacted.
Snowmobiles have typically had a variety of arrangements for controlling the endless belt of the powered traction units. The typical prior art traction units are single stage angle of attack. Accordingly, there has been a problem with prior art snowmobiles in that the angle of attack is either of a type which is better suited for racing or of a type that is better suited for trail riding. The attributes of each are that an angle of attack used for trail riding is a compromise between an angle better suited for deep snow and an angle better suited for riding where the snow is compacted and that a low angle of attack is more efficient on compacted snow. A snowmobile with the suspension/traction unit arranged and set up for racing generally has a very low angle of attack and limited travel in order to provide a very positive feel for the driver and to coordinate the suspension for the traction unit to the suspension for the front skis.
The prior art has not provided a snowmobile with a suspension/traction unit which has an angle of attack that is responsive and efficient in deep snow and is effective for high speed riding.